Bonding organic materials such as rubbers and plastics to metals is of great importance. Numerous articles provide a litany of mechanisms and solutions for bonding these distinct materials, with varying degrees of success. This is because different organic materials and metals have unique properties and varying degrees of compatibility.
For example, some organic materials have low energy surfaces while other organic materials have high energy surfaces. Some organic materials have plastic properties while other organic materials have elastomeric properties. Some organic materials have good heat resistance while other organic materials have poor heat resistance. Some organic materials have a high melt index while other organic materials have a low melt index. Organic materials may have different atoms which affect bonding properties, such as nitrogen containing materials, oxygen containing materials, silicon containing materials, halogen containing materials, sulfur containing materials, and so on.
Metals and metal alloys (collectively termed metals) possess varying characteristics. Metals vary in hardness/softness, corrosion resistance, toughness, wear resistance, resistance to chemical attack, tensile strength, types of oxides formed, and so on. With specific regard to magnesium, it is much more reactive than many other metals. Magnesium has a high sensitivity to salts such as chlorides. Magnesium also easily and quickly oxidizes. Magnesium oxide, formed by oxidation on a magnesium surface, is a very difficult surface on which to form a strong bond with other materials. Extreme care must be exercised with magnesium as fire and explosion hazards are associated with magnesium dust.
There are seemingly endless permutations of organic materials, and metals, all of which inherently have varying characteristics and properties. Improved bonding between specific types of organic materials and metals is therefore desired.
Furthermore, bonding organic materials to metals typically involves initially contacting the metal surface with a primer prior to joining the organic material with the metal. The primer serves improve adhesion between an adhesive and the metal. The primer, which strongly bonds with the adhesive, more strongly bonds to the metal than the adhesive. However, the use of a primer is not only time consuming, but also expensive. The use of additional chemicals such as primers and associated solvents presents disposal concerns and toxicity concerns. Bonding organic materials to metals without the need of a primer is therefore also desired.
Products made of an organic material bonded to a metal are used in many environments. Many of these products are used in harsh manufacturing environments. Manufacturing environments involve drastic and sudden changes in temperature and humidity, shock resistance (for example, to absorb the shock of a drop on concrete from a height of four feet), the ability to absorb vibrational movement, and resistance to petroleum based products, water-based cutting fluids, and industrial chemicals and solvents. There is a desire for products having organic materials to metals that maintain their integrity over time even in a manufacturing environment.